Battery pack with cells of different capacities

ABSTRACT

The disclosed embodiments provide a battery pack for use with a portable electronic device. The battery pack includes a first set of cells with different capacities electrically coupled in a parallel configuration. Cells within the first set of cells may also have different thicknesses and/or dimensions. The first set of cells is arranged within the battery pack to facilitate efficient use of space within a portable electronic device. For example, the first set of cells may be arranged to accommodate components in the portable electronic device.

BACKGROUND

1. Field

The present embodiments relate to batteries for portable electronicdevices. More specifically, the present embodiments relate to batterypacks with cells of different capacities, thicknesses, and/ordimensions.

2. Related Art

Rechargeable batteries are presently used to provide power to a widevariety of portable electronic devices, including laptop computers,mobile phones, PDAs, digital music players and cordless power tools. Themost commonly used type of rechargeable battery is a lithium battery,which can include a lithium-ion or a lithium-polymer battery.

Lithium-polymer batteries often include cells that are packaged inflexible pouches. Such pouches are typically lightweight and inexpensiveto manufacture. Moreover, pouches may be tailored to various celldimensions, allowing lithium-polymer batteries to be used inspace-constrained portable electronic devices such as mobile phones,laptop computers, and/or digital cameras. For example, a lithium-polymerbattery cell may achieve a packaging efficiency of 90-95% by enclosing ajelly roll and electrolyte in a foil pouch. Multiple pouches may then beplaced side-by-side within a portable electronic device and electricallycoupled in series and/or in parallel to form a battery for the portableelectronic device.

However, efficient use of space may be limited by the use andarrangement of cells in existing battery pack architectures. Inparticular, battery packs typically contain cells of the same capacity,size, and dimensions. The physical arrangement of the cells mayadditionally mirror the electrical configuration of the cells. Forexample, a six-cell battery pack may include six lithium-polymer cellsof the same size and capacity configured in a two in series, three inparallel (2s3p) configuration. Within the battery pack, two rows ofthree cells placed side-by-side may be stacked on top of each other;each row may be electrically coupled in a parallel configuration and thetwo rows electrically coupled in a series configuration. Consequently,the battery pack may require space in a portable electronic device thatis at least the length of each cell, twice the thickness of each cell,and three times the width of each cell. Furthermore, the battery packmay be unable to utilize free space in the portable electronic devicethat is outside of a rectangular space reserved for the battery pack.

Hence, the use of portable electronic devices may be facilitated byimprovements related to the packaging efficiency, capacity, form factor,cost, design, and/or manufacturing of battery packs containinglithium-polymer battery cells.

SUMMARY

The disclosed embodiments provide a battery pack for use with a portableelectronic device. The battery pack includes a first set of cells withdifferent capacities electrically coupled in a parallel configuration.Cells within the first set of cells may also have different thicknessesand/or dimensions. The first set of cells is arranged within the batterypack to facilitate efficient use of space within a portable electronicdevice. For example, the first set of cells may be arranged toaccommodate components in the portable electronic device.

In some embodiments, the battery pack also includes a second set ofcells with different capacities electrically coupled in a parallelconfiguration. The first set of cells and the second set of cells may beelectrically coupled in a series configuration if the first set of cellsand the second set of cells have substantially the same capacity.

In some embodiments, the first set of cells is stacked, placedside-by-side, or placed top-to-bottom within the battery pack.

In some embodiments, one or more of the first set of cells correspond toa lithium-polymer cell.

In some embodiments, one or more of the first set of cells include:

-   -   (i) a jelly roll containing layers which are wound together,        including a cathode with an active coating, a separator, and an        anode with an active coating; and    -   (ii) a pouch enclosing the jelly roll.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a battery pack in accordance with an embodiment.

FIG. 2 shows a cross-sectional view of a battery pack in accordance withan embodiment.

FIG. 3 shows a battery cell in accordance with an embodiment.

FIG. 4 shows a flowchart illustrating the process of providing a powersource in accordance with an embodiment.

FIG. 5 shows a portable electronic device in accordance with anembodiment.

In the figures, like reference numerals refer to the same figureelements.

DETAILED DESCRIPTION

The following description is presented to enable any person skilled inthe art to make and use the embodiments, and is provided in the contextof a particular application and its requirements. Various modificationsto the disclosed embodiments will be readily apparent to those skilledin the art, and the general principles defined herein may be applied toother embodiments and applications without departing from the spirit andscope of the present disclosure. Thus, the present invention is notlimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features disclosed herein.

The data structures and code described in this detailed description aretypically stored on a computer-readable storage medium, which may be anydevice or medium that can store code and/or data for use by a computersystem. The computer-readable storage medium includes, but is notlimited to, volatile memory, non-volatile memory, magnetic and opticalstorage devices such as disk drives, magnetic tape, CDs (compact discs),DVDs (digital versatile discs or digital video discs), or other mediacapable of storing code and/or data now known or later developed.

The methods and processes described in the detailed description sectioncan be embodied as code and/or data, which can be stored in acomputer-readable storage medium as described above. When a computersystem reads and executes the code and/or data stored on thecomputer-readable storage medium, the computer system performs themethods and processes embodied as data structures and code and storedwithin the computer-readable storage medium.

Furthermore, methods and processes described herein can be included inhardware modules or apparatus. These modules or apparatus may include,but are not limited to, an application-specific integrated circuit(ASIC) chip, a field-programmable gate array (FPGA), a dedicated orshared processor that executes a particular software module or a pieceof code at a particular time, and/or other programmable-logic devicesnow known or later developed. When the hardware modules or apparatus areactivated, they perform the methods and processes included within them.

Embodiments provide a battery pack with multiple cells of differentcapacities, thicknesses, and/or dimensions. The cells may also bearranged to facilitate efficient use of space in a portable electronicdevice. For example, the cells may be stacked, placed side-by-side,and/or placed top-to-bottom to accommodate components in a mobile phone,laptop computer, and/or tablet computer.

In addition, the cells may be electrically coupled in a series and/orparallel configuration. In particular, the battery pack may include afirst set of cells with different capacities electrically coupled in aparallel configuration. The battery pack may also include a second setof cells with different capacities electrically coupled in a parallelconfiguration. The first and second sets of cells may then beelectrically coupled in a series configuration if the first and secondsets of cells have substantially the same capacity.

FIG. 1 shows a battery pack 100 in accordance with an embodiment.Battery pack 100 may supply power to a portable electronic device suchas a laptop computer, mobile phone, tablet computer, personal digitalassistant (PDA), portable media player, digital camera, and/or othertype of battery-powered electronic device.

As shown in FIG. 1, battery pack 100 includes a number of cells 102-112.Cells 102-112 may correspond to rechargeable (e.g., secondary) cellssuch as nickel-cadmium (Ni—Cd) cells, nickel-metal-hydride (Ni—MH)cells, lithium-ion cells, and/or lithium-polymer cells. For example, oneor more cells 102-112 may correspond to lithium-polymer cells, each ofwhich includes a jelly roll of layers wound together (e.g., a cathodewith an active coating, a separator, and an anode with an activecoating), and a flexible pouch enclosing the jelly roll. Lithium-polymercells are discussed in further detail below with respect to FIG. 3.

In one or more embodiments, cells 102-112 have different capacities,thicknesses, and/or dimensions. For example, cells 102-104 may each havea capacity of 3.2 Ah, cells 106-108 may each have a capacity of 1.5 Ah,and cells 110-112 may each have a capacity of 1.7 Ah. Similarly, cells102-104 may be longer, thicker, and/or wider than cells 106-112, andcells 106-108 may be longer, thicker, and/or wider than cells 110-112.

Cells 102-112 may also be electrically coupled in a series and/orparallel configuration. In particular, a first set of cells 102, 106,and 110 with different capacities may be electrically coupled in aparallel configuration, and a second set of cells 104, 108, and 112 withdifferent capacities may also be electrically coupled in a parallelconfiguration. Because the first set of cells and the second set ofcells have substantially the same overall capacity, the first and secondsets of cells may be electrically coupled in a series configuration. Inother words, cells 102-112 may be electrically coupled in a two inseries, three in parallel (2s3p) configuration.

More specifically, the selection, electrical configuration, and/orarrangement of cells 102-112 may be based on the physical and/orelectrical requirements of the portable electronic device. First, cells102-112 may be selected for use in battery pack 100 and/or electricallycoupled within battery pack 100 to meet the electrical (e.g., voltage,capacity, etc.) demands of components (e.g., printed circuit boards(PCBs), processors, memory, storage, display, optical drives, etc.) inthe portable electronic device. For example, cell 106 may beelectrically coupled in parallel to cell 110, and cell 108 may beelectrically coupled in parallel to cell 112 to give the electricallycoupled cells 106 and 110 and cells 108 and 112 the same capacity ascell 102 and cell 104 (e.g., 3.2 Ah). Cell 102, cell 104, cells 106 and110, and cells 108 and 112 may then be electrically coupled in series toincrease the voltage of battery pack 100.

Along the same lines, cells 102-112 may be selected for use in batterypack 100 and/or arranged within battery pack 100 to facilitate efficientuse of space in the portable electronic device. For example, cells102-112 may be selected for use in battery pack 100 and stacked, placedside-by-side, and/or placed top-to-bottom within battery pack 110 toaccommodate components in a mobile phone, laptop computer, and/or tabletcomputer. Battery pack 100 may thus include an asymmetric design thatmaximizes the use of free space within the portable electronic device.In turn, battery pack 100 may provide greater capacity, packagingefficiency, and/or voltage than battery packs containing cells with thesame capacity, dimensions, and/or thickness. Battery packs containingcells of varying sizes and/or dimensions are discussed in further detailbelow with respect to FIGS. 2-3.

FIG. 2 shows a cross-sectional view of a battery pack in accordance withan embodiment. The battery pack includes three cells 202-206 ofdifferent thicknesses and/or sizes. As shown in FIG. 2, cell 202 is thethinnest, cell 204 is of medium thickness, and cell 206 is the thickest.In addition, cells 202-206 may be arranged in the battery pack based onan asymmetric design that allows the battery pack to fill up the freespace within a portable electronic device. For example, cells 202-206may be positioned within the battery pack to take up a curved region ofspace inside a mobile phone, laptop computer, portable media player,digital camera, and/or PDA.

FIG. 3 shows a battery cell 300 in accordance with an embodiment.Battery cell 300 may correspond to a lithium-polymer cell that is usedto power a portable electronic device. Battery cell 300 includes a jellyroll 302 containing a number of layers which are wound together,including a cathode with an active coating, a separator, and an anodewith an active coating. More specifically, jelly roll 302 may includeone strip of cathode material (e.g., aluminum foil coated with a lithiumcompound) and one strip of anode material (e.g., copper foil coated withcarbon) separated by one strip of separator material (e.g., conductingpolymer electrolyte). The cathode, anode, and separator layers may thenbe wound on a mandrel to form a spirally wound structure. Jelly rollsare well known in the art and will not be described further.

During assembly of battery cell 300, jelly roll 302 is enclosed in aflexible pouch, which is formed by folding a flexible sheet along a foldline 312. For example, the flexible sheet may be made of aluminum with apolymer film, such as polypropylene. After the flexible sheet is folded,the flexible sheet can be sealed, for example by applying heat along aside seal 310 and along a terrace seal 308.

Jelly roll 302 also includes a set of conductive tabs 306 coupled to thecathode and the anode. Conductive tabs 306 may extend through seals inthe pouch (for example, formed using sealing tape 304) to provideterminals for battery cell 300. Conductive tabs 306 may then be used toelectrically couple battery cell 300 with one or more other batterycells to form a battery pack, such as battery pack 100 of FIG. 1.

For example, battery cell 300 may belong to a first set of cells in thebattery pack with different capacities electrically coupled in aparallel configuration. The battery pack may also include a second setof cells with different capacities coupled in a parallel configuration.The first set of cells may then be electrically coupled to the secondset of cells in a series configuration if the first and second sets ofcells have substantially the same capacity. Consequently, conductivetabs 306 may allow battery cell 300 to be used in a battery packcontaining cells of different capacities that are electrically coupledin a parallel and/or a series-and-parallel configuration.

FIG. 4 shows a flowchart illustrating the process of providing a powersource in accordance with an embodiment. In one or more embodiments, oneor more of the steps may be omitted, repeated, and/or performed in adifferent order. Accordingly, the specific arrangement of steps shown inFIG. 4 should not be construed as limiting the scope of the embodiments.

Initially, a first set of cells with different capacities is arrangedwithin a battery pack to facilitate use of space within a portableelectronic device (operation 402). The cells may be selected forphysical (e.g., dimension, thickness, etc.) and/or electrical (e.g.,capacity, voltage, etc.) characteristics that allow the cells toadequately supply power to and/or accommodate components in the portableelectronic device. The cells may correspond to lithium-polymer cellsand/or other types of rechargeable battery cells. Next, the first set ofcells is electrically coupled in a parallel configuration (operation404). The parallel configuration may increase both the capacity andredundancy of the battery pack.

A second set of cells with different capacities is also arranged withinthe battery pack (operation 406) and electrically coupled in a parallelconfiguration (operation 408). As with the first set of cells, thesecond set of cells may be selected, electrically coupled, and/orarranged within the battery pack to meet the electrical and physicalrequirements of components in the portable electronic device.

Finally, the first set of cells is connected to the second set of cellsin a series configuration (operation 410). The series connection of thetwo sets of cells may increase the voltage of the battery pack.Moreover, the first and second sets of cells may be electrically coupledin series if the first and second sets of cells have substantially thesame capacity.

The above-described rechargeable battery pack can generally be used inany type of electronic device. For example, FIG. 5 illustrates aportable electronic device 500 which includes a processor 502, a memory504 and a display 508, which are all powered by a battery 506. Portableelectronic device 500 may correspond to a laptop computer, tabletcomputer, mobile phone, PDA, portable media player, digital camera,and/or other type of battery-powered electronic device. Battery 506 maycorrespond to a battery pack that includes one or more rechargeablebattery cells. In particular, the battery pack may include a first setof cells with different capacities electrically coupled in a parallelconfiguration. The battery pack may also include a second set of cellswith different capacities electrically coupled in a parallelconfiguration. The first and second sets of cells may be electricallycoupled in a series configuration if the first and second sets of cellshave substantially the same capacity.

The foregoing descriptions of various embodiments have been presentedonly for purposes of illustration and description. They are not intendedto be exhaustive or to limit the present invention to the formsdisclosed. Accordingly, many modifications and variations will beapparent to practitioners skilled in the art. Additionally, the abovedisclosure is not intended to limit the present invention.

1. A battery pack, comprising: a first set of cells with differentcapacities electrically coupled in a parallel configuration, wherein thefirst set of cells is arranged within the battery pack to facilitateefficient use of space within a portable electronic device.
 2. Thebattery pack of claim 1, further comprising: a second set of cells withdifferent capacities electrically coupled in a parallel configuration,wherein the first set of cells and the second set of cells havesubstantially the same capacity, and wherein the first set of cells andthe second set of cells are electrically coupled in a seriesconfiguration.
 3. The battery pack of claim 1, wherein the first set ofcells is stacked, placed side-by-side, or placed top-to-bottom withinthe battery pack.
 4. The battery pack of claim 1, wherein cells withinthe first set of cells have different thicknesses.
 5. The battery packof claim 1, wherein cells within the first set of cells have differentdimensions.
 6. The battery pack of claim 1, wherein one or more of thefirst set of cells correspond to a lithium-polymer cell.
 7. The batterypack of claim 1, wherein one or more of the first set of cells comprise:a jelly roll comprising layers which are wound together, including acathode with an active coating, a separator, and an anode with an activecoating; and a pouch enclosing the jelly roll.
 8. A method for providinga power source for a portable electronic device, comprising: arranging afirst set of cells with different capacities within a battery pack tofacilitate efficient use of space within the portable electronic device;and electrically coupling the first set of cells in a parallelconfiguration.
 9. The method of claim 8, further comprising: arranging asecond set of cells with different capacities within the battery pack,wherein the second set of cells has substantially the same capacity asthe first set of cells; electrically coupling the second set of cells ina parallel configuration; and electrically coupling the first set ofcells and the second set of cells in a series configuration.
 10. Themethod of claim 8, wherein the first set of cells is stacked, placedside-by-side, or placed top-to-bottom within the battery pack.
 11. Themethod of claim 8, wherein the first set of cells is arranged toaccommodate components in the portable electronic device.
 12. The methodof claim 8, wherein cells within the first set of cells have differentdimensions.
 13. The method of claim 8, wherein one or more of the firstset of cells comprise: a jelly roll comprising layers which are woundtogether, including a cathode with an active coating, a separator, andan anode with an active coating; and a pouch enclosing the jelly roll.14. A portable electronic device, comprising: a set of componentspowered by a battery pack; and the battery pack, comprising: a first setof cells with different capacities electrically coupled in a parallelconfiguration, wherein the first set of cells is arranged within thebattery pack to facilitate efficient use of space within a portableelectronic device.
 15. The portable electronic device of claim 14,wherein the battery pack further comprises: a second set of cells withdifferent capacities electrically coupled in a parallel configuration,wherein the first set of cells and the second set of cells havesubstantially the same capacity, and wherein the first set of cells andthe second set of cells are electrically coupled in a seriesconfiguration.
 16. The portable electronic device of claim 14, whereinthe first set of cells is stacked, placed side-by-side, or placedtop-to-bottom within the battery pack.
 17. The portable electronicdevice of claim 14, wherein the first set of cells is arranged toaccommodate the components in the portable electronic device.
 18. Theportable electronic device of claim 14, wherein cells within the firstset of cells have different thicknesses or dimensions.
 19. The portableelectronic device of claim 14, wherein one or more of the first set ofcells correspond to a lithium-polymer cell.
 20. The portable electronicdevice of claim 14, wherein one or more of the first set of cellscomprise: a jelly roll comprising layers which are wound together,including a cathode with an active coating, a separator, and an anodewith an active coating; and a pouch enclosing the jelly roll.